Spring sash balance



`11am. 8, 1952 P, A. Lus-nc; 2,581,423

SPRING sAsH BALANCE Filed May 3, 194e 2 SHEETS- SHEET 2 Patented Jan. 8, 1952 SPRING SASH BALANCE Peter A. Lustig, Detroit, Mich., assigner to Star Detroit, Mich., a corpora- Products Company, tion of Michigan Application May 3, 1946, Serial No.`667,135

1 Claim. (Cl. 16-198) This invention relates to sash balancing devices .and in particular to spring-actuated sash balances.

One object of this invention is to provide an improved spring sash balance having the spring completely enclosed within the spring drum, thereby protecting the spring and also providing bearing surfaces for the drum at the opposite ends thereof.

nother object is-to provide a spring sash balance as set forth in the preceding object, -wherein the spring drum comprises two interfitting cupshaped members enclosing the spring and preferably having integral struck-up portions for anchoring the end of the spring.

VAnother object is to provide a spring sash balance as set forth in the preceding objects wherein improved means isprovided for attaching the end of the tape-to the drum.

Another object is to provide a spring sash balance as set forth in the preceding objects wherein the two halves of the spring drum .are united by a tab engaging a slot in the intertting anges of the drum halves.

.Another object is to provide a spring sash balance having a spring drumy rotatably mounted in a casing of improveddesign, the parts of which are easily adapted to mass production and assembly.

Another object is to provide a spring sash balance as set forth in the object immediately preceding, wherein the casing includes a construction .adapted to be secured to any one of a variety of .sizes .and shapes of attachment plates without making any changes in the casing or drum.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein:

Figure 1 is a cross section through an upper corner of a window frame showing a side elevation, partly in section, of a sash balance according to a preferred embodiment of the invention;

wFigure 2 is an approximately horizontal section along the broken line 2-2 in Figure 1;

Figure 3 is a vertical section along the line 3 3 in Figure 1;

Figure 4 is a left-hand elevational view of the spring drum mounted inside the spring sash balance in Figure 1;

Figure 5 is a perspective view of one of the casing halves employed in the sash balance of Figure 1;

Figure 6 is a perspective view of the other casing-half intertting with the casing half shown in'Figure 5;

vFigure 7 isa perspective view of a mounting plate or face plate used in the spring sash balance of Figure l;

Figure 8 is a front elevation of the outer spring drum half used in the spring sash balance of Figure 1;

Figure 9 is a right-hand side elevation of a portion of Figure 8; f

Figure l0 is a front elevation of the inner spring drum half tted into the corresponding half shown in Figure 8;

Figure 11 is a left-hand tion of Figure 1 0;

Figure 12 is a perspective view of the axle used in the sash balance of Figure 1, and;

Figure 13 is a cross-section along the line i3-I 3 in Figure 1.

Referring to the drawings in detail, Figure 1 shows a preferred embodiment of the spring sash balance of the invention, generally designated IG, as mounted in an upper corner of a window frame, generally designated I I having side inembers I2 (one only being shown) and a top cross member I3. The side member I2 is provided with a recess I for receiving the end of the cross member I3 and the latter is also provided with an aperture I5 through which the sash balance I0 is inserted and secured.

The sash balance I0 is provided with a casing generally designated I6, composed of interi'itting halves Il' and I8 to which a mounting plate or face plate i9 is secured (Figures 5, 6 and 7). The casingfhaif il consists of a side plate .29 having a partially semi-circularedge 2l and tabs 22 bent inwardly at intervals along the edge 2E; Arcuate slots 23 in a circular pattern are formed in the side plates 2|. Integral with the side plate 20 and bent approximately at right angles thereto is a bottom plate 211 having an elongated rectangular aperture 25 therethrough near the end 26 thereof and an approximately rectangular notch 2l in the opposite end 2S. The bottom plate 24 is slightly shorter than the side plate 20 so that the ends 28 and 28 are inset from the edge 2| by approximately the thickness of the casing half I3 so as to provide a ush joint therebetween when the halves I 'i and I8 are assembled.

The casing half I8 consists of a side plate 229 having an outline corresponding to the outline of the side plate 20. The side plate 29 is provided with arcuate slots 30 disposed in a circular path corresponding to and immediately opposite the arcuate slots 23 in the side plate 2t. The casing half I8 is also provided with an edge flange 3l bent substantially at right angles to the side plate 29 and of outline slightly smaller in size side elevation of a por- 3 than the outline of the edge 2I so as to iit into the space inside the tabs 22 when the halves I1 and I8 are assembled.

The mounting plate or face plate I9 consists of an approximately rectangular plate 32 having a semi-circular end 33 with a countersunk conical portion 34 therein having a hole 35 for receiving a fastener 36 (Figure l). Near the opposite end 31, the plate 32 is provided with an approximately rectangular portion 38 struck-up approximately at right angles to the plate 32 and leaving a rectangular' aperture 39 therein. Intermediate the ends 33 and 31, the plate 32 is provided with a second struck-up portion 45, also of approximately rectangular outline, but inclined relatively to the plate 32 and leaving an approximately rectangular aperture or recess 4I therein.

The casing halves I1 and I8 in assembly are also interconnected by a tubular axle 42 (Figure 12) formed of a single piece of sheet material, such as sheet metal, bent into a cylinder with its opposite edges 43 and 44 spaced apart from one another by a slight gap. The opposite ends 45 and 45 are provided with integral projecting tabs 41 and 48 respectively spaced in the same relationship to enter the arcuate slots 35 and 23 in the casing halves IB and I1 respectively.

Rotatably mounted upon the axle 42 inside the casing I6 is an approximately cylindrical spring drum 55 composed of intertting or mating cupshaped halves I and 52 (Figures 8 to 11 inclusive). The outer drum half 5l consists of a side plate or end 53 having a central bore 55 therein for receiving the axle 42 and also having an edge iiange 55 bent approximately at right angles to the side plate 53. The side plate 53, surrounding the bore 54, is struck outwardly to provide an annular boss 55 for spacing the side plate 53 slightly inwardly of the side plate 25 of the casing half I1 (Figure 3). A rectangular notch 51 is provided in an edge of the flange 55. An inwardly struck tab 58 is formed in the flange 55, leaving an approximately rectangular opening 55.

The corresponding or inner drum half 52 (Figures and 11) is similarly provided with an edge ,flange 65 of slightly smaller diametein than the edge ilange 55 so as to nest therein. .A similar bore 6I is provided, surrounding by a similar boss 62 for the same purpose as the boss 55. The edge nange 63 is provided with a pair of spaced rectangular apertures 53 and E4, the former being o1" a size corresponding with and adapted to receive the tab 58 when the two halves 5l and 52 are nested (Figures 1 and 13). This construction prevents relative rotation between the drum halves 5I and 52.

The flange 65 is also provided with an inwardly struck tab 55 leaving an aperture 56 of approximately rectangular outline, the tab 65 being provided as an anchorage for the outer end 31 of a spiral spring 65, the latter being bent relatively to the former around the edge of the tab (Figure 1). The inner end 59 of the spiral spring 58 is likewise bent so as to enter the gap between the axle edges 43 and 44 (Figure 12). The sash balance IG is likewise provided with a flexible connecting member (Figure l) such as a steel tape having its lower end 1I engaged by a U-shaped member 12, the middle of which encircles a ring or rectangular loop 13 which is attached to the upper edge of the window sash and the ends of which are secured to the end 1i of the tape 10, as by welding. The inner end 4 14 of the tape 10 (Figure 1) is connected to the drum 50 as described below.

In the assembly of the sash balance of this invention, the drum halves 5I and 52 are nested by pushing the latter within the :former (Figures 8 and l0) until the tab 58 snaps into the aperture 63 (Figures 4 and 13). The end 14 of the connecting member or tape 10 is then threaded inwardly through the aperture 66 and bent at that point, then threaded outwardly through the aperture 64 with its tip overlying the portion 'I5 of the edge flange 55 lying between the aperture 51 and the aperture 59, with the result shown in Figure 1.' The tape 15 is then wound upon the drum 55 in the manner shown in Figures 1 and 4.

Meanwhile, the bottom plate 24 of the casing half I1 is secured to the face plate or mounting plate I9 in any suitable way as by spot welding at any convenient locations such as the points 16 (Figure 5) During welding, the struck-up portion 45 serves as a locating member by engaging the outer edge of the aperture 25, and the struckup portion 38 projects upwardly through the notch 21.

The axle 42 is then inserted through the holes 54 and 6i in the drum halves 5l and 52, and its tabs 43 inserted through the holes 23 in the casing half I1. rlhe casing half I5 is then brought together over the drum 55 and casing half I1 so as to enclose them, and at the same time, the tabs 41 on the exposed end of the axle 42 are inserted through the slots 3G. When the casing I6 is thus completely assembled, and the end 1I of the tape 'iii has been passed through the apertures 21 and 39, the tabs 41 and 48 are turned over (Figures 1 and 3) and recessed into the side plates 25 and 23 so as to be ilush therewith and thus anchor the assembly together. 1t will be evident trom Figure 3 that the clinching of the axle tabs 41 and 58 against the side plates 2l) and 2Q in this manner at the same time brings the outer surfaces oi the annular bosses 56 and 62 into frictional engagement with the inner surfaces of the side plates 25 and 29 respectively, thus setting up a irictional drag therebetween. The loop 13 is then attached to the lower end 1I of the tape 'lil and the sash balance is completely assembled.

In the mounting of the sash balance, the end 3'! oi' the face plate or mounting plate I3 is inserted in the notch I4 below the top cross membei' I3 of the window frame I! and the opposite end 33 secured thereto by inserting a fastener 3E through the hole 35. As there are two such oppositely facing sash balances I5 mounted at opposite ends of the top cross member I3, their loops 13 are connected to the upper end of the sash and the assembly is complete.

In the operation of the invention, when the sash is drawn downwardly to close the window, the tapes 10 move downwardly, rotating the drum 5E) and winding up the coil springs 58, counterbalancing the weight oi' the sash. When the window is opened, the spring 58 unwinds, but the tendency of the window sash to descend is counteracted by the tendency or" the spring 58 to wind up. The iorce thus generated counterbalances the sash in all its positions between its fully open and fully closed positions. Moreover, when the spring 58 is wound up during operation in this manner, a force is built up which has to be counteracted in order to hold the window in its raised position. The rictional drag set up between the annular bosses 53 and 62 and the adjacent inner surfaces of the side plates 29 and 29 provides a suicient retarding effect to accomplish this result.

While I have shown and described my inven tion in detail, it is to be understood that the same is to be limited only by the appended claim, for many changes may be made without departing from the spirit and scope of my invention.

What I claim is:

A spring sash balance comprising a casing, an axle mounted in said casing, a drum mounted in said casing comprising a pair of oppositely disposed cupped cylindrical members having peripheral flanges arranged in nesting engagement and engaging said axle at axially spaced locations thereon, a spring within said drum connected at one end to said axle and at the other end to said drum, and an elongated exible element connected to said drum and windable on the outside of the outermost flange ior attachment to the sash, one of said drum members having a peripheral recess and the other drum member having a peripheral projection extending into said recess whereby to retain said members in nesting engagement.

PETER A. LUSTIG.

REFERENCE S CITED UNITED STATES PATENTS Number Name Date 462,725 McArthur Nov. 10, 1891 913,799 Zund-Burguet Mar. 2, 1909 939,971 Brennan Nov. 16, 1909 1,082,034 MacLaughlin et al. Dec. 23, 1913 1,762,821 Kersting June 10, 19.30

2,226,721 Hui Dec. 31, 1940 2,241,969 Tappan May 13, 1941 2,242,650 Mantz 'May 20, 1941 FOREIGN PATENTS Number Country Date 372,799 France Mar. 1, 1907 

